This invention relates to a system for the collection and transmission of road traffic information.
In the control of vehicular traffic on roads by the on-line traffic signal control system, provision of the information on traffic volume as input data is an indispensable requirement. This information changes minute by minute.
Heretofore, vehicle detecting devices such as the ultrasonic system and the loop system have been buried under road surfaces of traffic lanes near intersections or installed aerially above such road surfaces and used for measuring the traffic volume of vehicles passing through these intersections, spatial and chronological vehicular occupancy of roads and duration of traffic congestion, and the results of the measurement have been utilized as the information on road traffic (IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, Vol VT 19, No. 1, Feb. 1970, for example). The detection area covered by each vehicular detecting device is limited to only several square meters. In the case of a road containing a plurality of traffic lanes, therefore, there must be installed one detecting device for each of the lanes. To make the matter worse, the cost required for the installation of each detecting device is relatively high. For this reason, an attempt to use these devices to obtain accurate spatial traffic information on all the road areas centering around an intersection requires an enormous expenditure. If the number of these devices so distributed in all the lanes is decreased to lower the expense, it is no longer possible to obtain accurate traffic information.
An object of this invention is to provide a system for the collection and transmission of traffic information, which system is capable of accurately measuring the flow of vehicles on sections of roads 300 to 500 meters in length, for example.
Another object of this invention is to provide a system for the collection and transmission of traffic information, which system is capable of counting the number of vehicles passing a specific area of the road.
Still another object of this invention is to provide a system for the collection and transmission of traffic information, which system is capable of measuring speeds of vehicles passing a specific area of the road.
A further object of this invention is to provide a system for the collection and transmission of traffic information, which system is capable of readily transmitting the traffic information to be collected.